Circuit Lake

This circuit is for detecting any audio signal with justable noise offset. It could be used to generate a radio mute signal eg. from a PDA. The circuit is consisting of:

This is a really cheap and probably illegal shortwave transmitter, don’t build it. It just feeds the output from an LM386 audio amplifier directly into the power pin of a crystal oscillator can to produce AM-modulated shortwave radio frequencies. This works better than one might expect — this particular oscillator seems to provide a stable […]